CHAPTER 1I: APPROACH AND METHODS 46
In spite of environmental changes that have occurred and their effects on species assemblages, many
communities remain relatively intact and functional or have the potential for recovery or increased
functionality. A positive result can occur by implementing actions to more effectively manage, protect
and conserve habitats while promoting compatible human use of lands.
CLASSIFYING AND RANKING WILDLIFE HABITATS IN MISSISSIPPI
The state’s NHP Ecological Community List was simplified and used in the CWCS to expedite the
process of associating SGCN with their habitats and communities. The NHP list is holistic and
ecologically based. Terrestrial habitats are typically classified by a combination of the dominant
vegetation cover and moisture availability. Aquatic habitats are primarily classified by ecoregion,
stream size and/or drainage, differences in soil type and topography. The National Wetlands Inventory
(NWI) provides a basic classification technique for all types of wetlands found throughout the United
States. Later modifications to the NWI System were designed to make the levels of the classification
hierarchy more consistent and applicable to marine environments. The major categories of this
classification are system (marine and estuarine types), subsystem (intertidal and subtidal), class
(substrate type), subclass (exposure/energy levels), and modifiers (i.e. water depth, salinity, etc.). The
NHP list includes 159 natural, semi-natural, managed, weedy and probable subtypes which have been
assigned conservation priority ranks indicating their relative endangerment or abundance (See Appendix
XII for information on interpreting those ranks).
The primary factors the NHP uses for assessing community status are the total number of occurrences
(e.g., forest stands) and the total acreage occupied by the community. Secondary factors include the
geographic range over which the community occurs, threats and the integrity of the occurrences.
Because detailed information on these factors may not be available, especially for poorly understood
communities, preliminary assessments are often based on the following: geographic range over which
the community occurs; long-term trends across this range; short-term trends (i.e., threats); degree of site/
environmental specificity exhibited by the community; and imperilment or rarity across the range.
For the purposes of this CWCS, the 159 ecological community types used in the NHP were combined
into 17 broad habitat types and 64 subtypes. The table on the next page lists the CWCS habitats which
are generally organized on the basis of land type, vegetation and the availability of moisture. Within the
17 habitat types, 64 subtypes were further defined by factors affecting natural communities such as: soil
type, water availability, vegetation, water chemistry, region and stream size. The ecoregions in which
these types and subtypes are located are also listed in the following table.
To aid the reader a table providing a crosswalk of the NHP ecological community types with the CWCS
habitat types and subtypes is included in Appendix XI.